Telephone conferencing systems have been available for many years. An audio conferencing system may include an audio bridge that connects calls or lines to particular system resources for processing. An audio bridge may include, for example, a processor that controls the system, a plurality of digital signal processing (“DSP”) nodes that perform call processing, a plurality of network interface connections that connect to call participants, and a time division multiplexing (“TDM”) bus for transmitting conferences information to and from the DSP nodes. A conferencing system including these components is described, for example, in U.S. Pat. No. 5,495,522, entitled “Method and Apparatus for Audio Tele-conferencing a Plurality of Phone Channels,” the disclosure of which is incorporated herein by reference.
As a significant disadvantage, conventional conferencing systems impose geometric increases in switching complexity as call volume increases. That is, each additional call connection may require an additional DSP unit, adding one connection to both the input and the output of intermediate switching circuitry. There remains a need for an audio conferencing architecture that can be more readily scaled to address increasing call capacity.